- Ancestors (parents, grandparents, or even great-grandparents). My favorite certificates are the ones that are usually the most tragic. They were filled out by a parent or grandparent of the deceased (usually a child in these cases). But, because of the close connection to the deceased, the certificate is usually pretty spot-on and thorough.
- Children. Talk about hit-or-miss. No certificate offers as much uncertainty as when a child of the deceased is the informant. I've gotten some that were surprisingly thorough and others that are truly head-scratching. When my great-grandmother died and her son supplied the information, he put "unknown" for both her parents. Now, I knew my great-grandmother and she talked about her parents often so you'd be hard pressed to find anyone in my family who didn't know who they were. I can only figure that he didn't read over the certificate very thoroughly before he signed it.
- Spouses. This is the most common informant I've found and usually one of the best. If I know the deceased had a living spouse, the certificate goes way up on my priority list of ones to get. I do find that while the deceased's parents are listed, little mistakes are often present and the maiden name of the deceased's mother is often missing.
- Other Relatives (cousins, aunts and uncles, nephews and nieces, etc.). Much the same as children, very hit-or-miss (but usually miss).
- Friends, Neighbors and Strangers. I don't know about you, but I rarely discuss my family tree with people I am unrelated to or who are uninterested in genealogy. If I were to die today, I can count very few people unrelated to me who would make a decent informant on my death certificate. I have found that this is often the case with relatives, thus these certificates are usually disappointing.
Obviously, any good genealogist goes after all the certificates available and I do. But I'm also not a wealthy person so when ordering a certificate, I want it to give me the most information (and most accurate information). That is why knowing or at least having an idea who the informant was is important to me.